Propeller three-dimensional model construction method

Abstract

The invention provides a propeller three-dimensional model construction method which comprises the steps that a three-dimensional modeling platform is constructed, the three-dimensional modeling platform comprises a user interaction interface and a model construction module, and the model construction module comprises a two-dimensional drawing unit and a three-dimensional drawing unit; inputting drawing parameters to the modeling platform from the user interaction interface, wherein the drawing parameters comprise the propeller type, the blade number and the screw pitch of the propeller; the two-dimensional drawing unit draws a two-dimensional general drawing of the propeller according to the drawing parameters, wherein the two-dimensional general drawing comprises an orthographic projection drawing, a side projection drawing and an extension profile drawing; the three-dimensional drawing unit extracts information of a plurality of key feature points at a plurality of feature radiuses from the two-dimensional general drawing; and the three-dimensional drawing unit draws the three-dimensional model according to the information of the key feature points at the feature radiuses, so that the design efficiency and accuracy of the propeller three-dimensional model are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ship design, in particular to a propeller three-dimensional model construction method. BACKGROUND

[0002] As the core propulsion component of the ship power device, the design and manufacturing precision of the propeller directly affect the rapidity, economy and safety of the ship. Due to the complex helix angle, rake angle and irregular curved surface shape of the blade, and the uneven thickness distribution, the traditional propeller modeling process not only consumes time and effort, but also needs to rely on the experience of the designer to manually process a large amount of two-dimensional drawings and data, which is easy to cause errors due to human operation. In the ship design process, a high-quality propeller three-dimensional model is the basis for subsequent water dynamic performance test, strength checking and numerical control processing. However, the existing technology has the following problems: low design response efficiency: at the initial stage of ship design, when the detailed theoretical design data is not yet perfect, the spatial adaptability of the propeller and rudder blades and other components needs to be quickly verified, but the traditional modeling method is difficult to quickly generate an adjustable three-dimensional model. Poor parameter adjustment flexibility: the core parameters of the propeller such as the number of blades, diameter and disc ratio need to be frequently iterated and optimized, and the traditional modeling method needs to repeatedly draw two-dimensional drawings and convert them into three-dimensional models, which has high parameter modification cost. Weak data correlation: the projection relationship between the three-view drawings of the two-dimensional general drawing and the numerical table of the blade shape and position is complex, and when manually converted into a three-dimensional model, data mismatching is easy to occur, which affects the model accuracy. SUMMARY

[0003] In view of the above-mentioned problems in the prior art of forming a propeller three-dimensional model, the present application provides a propeller three-dimensional model construction method to improve the accuracy and efficiency of the propeller three-dimensional model.

[0004] To achieve the above-mentioned and other related purposes, one aspect of the present application provides a propeller three-dimensional model construction method, which comprises:

[0005] A three-dimensional modeling platform is built, which comprises a user interaction interface and a model construction module, and the model construction module comprises a two-dimensional drawing unit and a three-dimensional drawing unit;

[0006] Drawing parameters are input to the user interaction interface of the modeling platform, which include the propeller type, the number of blades and the pitch;

[0007] The two-dimensional drawing unit draws a propeller two-dimensional general drawing according to the drawing parameters, which includes an orthographic projection drawing, a side projection drawing and a stretch contour drawing;

[0008] The three-dimensional drawing unit extracts information of a plurality of key feature points at a plurality of feature radii from the two-dimensional general drawing;

[0009] The three-dimensional drawing unit draws a three-dimensional model according to information of a plurality of key feature points at the plurality of feature radii.

[0010] Optionally, the three-dimensional modeling platform further comprises a data processing module for storing parameters input by a user and a database of a plurality of types of propeller blades.

[0011] Optionally, the database of the plurality of types of propeller blades comprises a table of blade profile dimensions and a table of blade section dimensions of an AU type propeller and an MAU type propeller.

[0012] Optionally, the two-dimensional drawing unit comprises:

[0013] determining the propeller parameters, the propeller parameters comprising a number of propeller blades, a disc ratio and a propeller diameter;

[0014] selecting a plurality of feature radii;

[0015] obtaining key parameters at the plurality of feature radii according to the table of blade profile dimensions and the table of blade section dimensions;

[0016] sequentially drawing the stretch profile drawing, the front projection drawing and the side projection drawing according to the parameters.

[0017] Optionally, the feature radii extracted by the three-dimensional drawing unit from the two-dimensional general drawing are consistent with the feature radii selected by the two-dimensional drawing unit when drawing the two-dimensional general drawing of the propeller.

[0018] Optionally, the three-dimensional modeling platform is an OLE automation server, and control of the three-dimensional modeling platform is realized through a programming language.

[0019] Optionally, further comprising: performing surface quality detection and structural strength detection on the three-dimensional model.

[0020] Optionally, the surface quality detection and structural strength detection on the three-dimensional model comprises:

[0021] detecting the fairness of a section curve;

[0022] a size of an arc at a leading edge of a propeller blade;

[0023] a thickness of a trailing edge of the propeller blade near a blade tip.

[0024] As described above, the propeller three-dimensional model construction method provided by the application has at least the following beneficial technical effects:

[0025] The propeller three-dimensional model construction method of the application can realize the rapid generation and flexible adjustment of the propeller model; based on the core parameters (propeller type, number of blades, pitch, etc.) input by the user and the background blade profile table data, the model construction module can automatically complete the two-dimensional general drawing and three-dimensional model generation, the three-dimensional modeling platform directly associates the model through the user interaction interface, and the model can be automatically updated after modifying the parameters (such as the blade helix angle, width changes in real time with the parameters), solving the pain point of "changing parameters requires redrawing the model" in traditional modeling. Through the strict projection relationship between the two-dimensional general drawing and the three-dimensional model, and the surface smoothness verification (curvature mutation control), the model accurately reflects the real shape of the propeller blade, and provides efficient and accurate three-dimensional data for subsequent propeller design, propeller hydrodynamic performance test, strength checking, numerical control machining, etc. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A structural schematic diagram of the propeller three-dimensional model construction method provided by the application is shown.

[0027] Figure 2a A drawing schematic diagram of a certain radius side view of the propeller is shown.

[0028] Figure 2b A drawing schematic diagram of a certain radius front view of the propeller is shown.

[0029] Figure 2c A drawing schematic diagram of a certain radius stretch contour diagram of the propeller is shown.

[0030] Figure 3a A schematic diagram of a side view of the propeller is shown.

[0031] Figure 3b A schematic diagram of a front view of the propeller is shown.

[0032] Figure 3c A schematic diagram of a stretch contour diagram of the propeller is shown. DETAILED DESCRIPTION

[0033] The embodiments of the application are described below through specific concrete examples, and those skilled in the art can easily understand other advantages and effects of the application from the disclosure of the specification. The application can also be implemented or applied by different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the application.

[0034] It should be noted that the diagrams provided in the embodiments only schematically illustrate the basic concepts of the present application, and although only components related to the present application are shown in the diagrams, the diagrams are not drawn according to the number, shape and size of the components in actual implementation, and the shape, number, positional relationship and proportion of each component in actual implementation can be changed arbitrarily under the premise of realizing the technical solutions of the present application, and the component layout form can also be more complex.

[0035] The embodiment provides a propeller three-dimensional model construction method, as shown in the figure, a flow chart of the propeller three-dimensional model construction method provided by the present application is shown; the propeller three-dimensional model construction method comprises the following steps: Figure 1

[0036] S1: build a three-dimensional modeling platform, the three-dimensional modeling platform comprises a user interactive interface and a model construction module, the model construction module comprises a two-dimensional drawing unit and a three-dimensional drawing unit

[0037] S2: input drawing parameters to the user interactive interface to the modeling platform, the drawing parameters comprise the propeller type, the number of leaves, the pitch

[0038] S3: the two-dimensional drawing unit draws a propeller two-dimensional general drawing according to the drawing parameters, the two-dimensional general drawing comprises an orthographic projection, a side projection and a stretch contour

[0039] S4: the three-dimensional drawing unit extracts information of a plurality of key feature points at a plurality of characteristic radii from the two-dimensional general drawing;

[0040] S5: the three-dimensional drawing unit draws a three-dimensional model according to the information of the plurality of key feature points at the plurality of characteristic radii.

[0041] Step S1: build a three-dimensional modeling platform, the three-dimensional modeling platform comprises a user interactive interface and a model construction module, the model construction module comprises a two-dimensional drawing unit and a three-dimensional drawing unit.

[0042] Specifically, the three-dimensional modeling platform supports the full-process automation of input parameters, automatic generation of two-dimensional views and three-dimensional model construction. Specifically, the user interactive interface adopts graphical window design, including parameter input area, preview area and operation button. Specifically, the parameter input area includes propeller type selection drop-down box, number of leaves, pitch P, diameter R input box, etc.; the preview area is used for real-time display of two-dimensional view and three-dimensional model thumbnail; the operation button includes generation, reset, export, etc.

[0043] ​Specifically, the three-dimensional modeling platform is an OLE automation server, including CATIA, SolidWorks, UG, etc. The control of the three-dimensional modeling platform can be realized through programming languages including VB language, Python, VBA, C#, etc., so as to complete the automatic operation of the propeller modeling. Specifically, the VB language is used for interaction with the three-dimensional modeling platform in the embodiment, the statements for accessing the three-dimensional software platform are embedded in the VB, the transmission of the design parameters and the execution of the modeling commands are realized. The GetObject or CreatObject method can be used to connect (start) the three-dimensional software platform when the three-dimensional software platform is running or not running.

[0044] Specifically, the two-dimensional drawing unit can automatically generate the stretch profile drawing, the front projection drawing and the side projection drawing according to the input drawing parameters and the propeller blade profile size table and the propeller blade section size table, and ensure that the characteristic point coordinates of the three-view drawing meet the projection relationship. The three-dimensional drawing unit extracts the characteristic points from the two-dimensional view, generates the space profile curve, constructs the blade entity, and has the rotation array function to generate the multi-blade model.

[0045] Optionally, the three-dimensional modeling platform further includes a data processing module for storing the parameters input by the user and the database of the multi-type propeller blade. Specifically, the database of the multi-type propeller blade includes the blade profile size table and the blade section size table of the AU type propeller and the MAU type propeller.

[0046] S2: input the drawing parameters to the modeling platform through the user interaction interface, the drawing parameters including the propeller type, the number of blades and the pitch. Optionally, the propeller type is preselected from the drop-down box of the user interaction interface as AU type or MAU type, and the data processing module automatically matches the corresponding profile size table and section size table. Specifically, the user inputs the number of blades (for example, 4, 5 or 6), the three-dimensional modeling platform automatically calculates the blade interval angle (for example, the interval angle between the blades of a 4-blade propeller is 90°, and the interval angle between the blades of a 5-blade propeller is 72°), and displays the interval angle on the interface; the user inputs the pitch value P or the pitch ratio, and the platform automatically checks the matching of the pitch value P or the pitch ratio with the diameter; the user inputs the diameter D of the propeller, the platform automatically calculates the radius R=D / 2, and automatically generates a plurality of characteristic radii (for example, 0.2R, 0.3R, …, 0.9R), and the user can manually add or delete the number of characteristic radii.

[0047] Optionally, the drawing parameters input to the user interaction interface further include the disc ratio, which is generally recommended according to the propeller type and can be manually adjusted by the user.

[0048] Step S3: the two-dimensional drawing unit draws the two-dimensional general drawing of the propeller according to the drawing parameters, and the two-dimensional general drawing includes the front projection drawing, the side projection drawing and the stretch profile drawing.

[0049] Generally, propeller design typically involves both theoretical design and graphical design methods. This embodiment employs the graphical design method. The steps for the two-dimensional drawing unit to draw the two-dimensional overall diagram of the propeller based on the drawing parameters include: First, determining the core parameters of the propeller, including the number of propeller blades, disk area ratio, propeller diameter, and pitch input by the user. For example, if the propeller has 4 blades, a diameter of D, a calculation radius R = D / 2, and a pitch of P; Second, selecting multiple feature radii. Generally, ≥6 feature radii are selected to ensure model accuracy. Further, 8-9 feature radii are selected (r = 0.2R, 0.3R, 0.4R…0.9R (0.95R)). The following steps are taken: First, use the following parameters as the drawing reference; second, obtain the key parameters at the characteristic radius of the propeller according to the propeller blade profile dimension table corresponding to the propeller model. The key parameters include: the distance 'a' from the generatrix to the blade guide edge, the distance 'b' from the generatrix to the blade guide edge, the blade width 'a+b', the blade thickness, and the distance from the guide edge to the thickest point of the blade; third, obtain the cross-sectional shape parameters at the characteristic radius of the propeller according to the propeller blade cross-sectional dimension table corresponding to the propeller model; fourth, draw the extended profile view, orthographic projection view, and side projection view according to the above parameters. The extended profile view unfolds the propeller blade along the helix into a planar view, directly reflecting the cross-sectional shape of the blade at different radial positions; the orthographic projection view is a profile view projected from the axial (front) view of the propeller, used to show the projected shape of the blade in the circumferential direction, reflecting the radial positional relationship between the blade and the axis; the side projection view is a profile view projected from the side view of the ship, used to show the axial tilt state of the blade, reflecting the spatial distribution of the blade in the axial direction.

[0050] Specifically, this embodiment uses an AU-type propeller as an example for illustrative purposes. The specific process of drawing the two-dimensional propeller general drawing is analyzed as follows: First, determine the number of blades, disk area ratio, and diameter of the AU-type propeller. Based on the propeller blade profile dimension table shown in Table 1, and according to the radius of the AU-type propeller, obtain the distance from the generatrix to the blade edge, the distance from the generatrix to the blade guide edge, the blade width, the blade thickness, and the distance from the blade guide edge to the thickest point. Then, based on the AU propeller blade cross-sectional dimension table shown in Table 2, obtain the cross-sectional shape at each radius point in the table. Finally, based on the propeller general drawing drawing method and the above cross-sectional data, draw the propeller orthographic projection, side projection, and extended profile.

[0051] Table 1 Propeller Blade Profile Dimensions

[0052]

[0053]

[0054] like Figure 2c The image shown is a schematic diagram illustrating the outline of a propeller at a certain radius. Figure 2bFig. 2 shows a drawing diagram of the front view of the propeller at a certain radius; Figure 2a Fig. 3 shows a drawing diagram of the side view of the propeller at a certain radius. The following embodiment is based on the drawing diagram of the side view of the propeller at a certain radius. Figures 2a-2c Fig. 4 shows a drawing diagram of the two-dimensional general view of the propeller, which specifically illustrates the drawing process of the two-dimensional general view of the propeller. Assuming that the radius is r and the pitch is P, as shown in Fig. 4, the drawing process of the two-dimensional general view of the propeller includes the following steps. Figure 2c As shown in Fig. 5, the drawing steps of the stretched profile diagram include the following steps. A plane rectangular coordinate system is established, and a horizontal reference line and a radial reference line are determined. The center of the tangent plane at the radius r is set as point A, OA is the radial reference line, OA = r, and a ray is drawn along the horizontal direction as the horizontal reference line. According to the pitch P, a point F on the horizontal reference line is determined, and the distance OF is P / (2π). The pitch angle is calculated. OF = P / (2π) is connected to OF, and AF is connected. Then, the pitch angle a of the tangent plane at the radius r is a = tg ∠OAF = P / (2πr). The tangent plane profile is drawn. A straight line NN' is drawn through point A on the tangent plane, and NN' is the tangent plane reference line at the radius r. Then, ∠N'AC = ∠OAF = θ. According to the data in Table 1, the leading edge point J and the trailing edge point H are determined on the line NN'. Specifically, the line AF is translated along the line NN' to the two ends of the tangent plane. The leading edge point J1 is obtained by measuring the distance b (the distance from the generatrix to the leading edge) from point A along the line NN' to one side. The trailing edge point H1 is obtained by measuring the distance a (the distance from the generatrix to the trailing edge) from point A along the line NN' to the other side. Then, the arc AH1' = a, and the arc AJ1' = b, where the values of a and b are obtained from Table 1. Specifically, since the propeller has a protruding part, the line NA is translated along the line AF, and the highest point S and the lowest point H of the tangent plane at the radius r are obtained. The distance from point S to the line NA is α, and the distance from point H to the line NA is β. The values of α and β are obtained by geometric measurement in the stretched profile diagram.

[0055] As shown in Fig. 6, the drawing steps of the front projection diagram include the following steps. The front projection diagram is the projection diagram of the tangent plane at the radius r along the FA direction. A circular arc is drawn on the front projection diagram with O as the center and r as the radius. The arc length AJ1 = b and the arc length AH1 = a are measured on the circular arc, and J1 and H1 are two points on the projection profile. Figure 2b As shown in Fig. 7, the drawing steps of the side projection diagram include the following steps. The side projection diagram is the projection diagram of the tangent plane at the radius r along the NI direction. A reference line OU is drawn on the side projection diagram. A horizontal line is drawn from A on the front projection diagram to intersect the line OU on the side projection diagram at point A'. Then, A' is the position of A on the side projection diagram. On the side projection diagram, A'L = α is measured horizontally forward from point A', and A'L' = β is measured horizontally backward from point A', where the values of α and β can be directly obtained from the tangent plane as shown in Fig. 5.

[0056] As shown in Fig. 8, the drawing steps of the side projection diagram include the following steps. The side projection diagram is the projection diagram of the tangent plane at the radius r along the NI direction. A reference line OU is drawn on the side projection diagram. A horizontal line is drawn from A on the front projection diagram to intersect the line OU on the side projection diagram at point A'. Then, A' is the position of A on the side projection diagram. On the side projection diagram, A'L = α is measured horizontally forward from point A', and A'L' = β is measured horizontally backward from point A', where the values of α and β can be directly obtained from the tangent plane as shown in Fig. 5. Figure 2a As shown in Fig. 8, the drawing steps of the side projection diagram include the following steps. The side projection diagram is the projection diagram of the tangent plane at the radius r along the NI direction. A reference line OU is drawn on the side projection diagram. A horizontal line is drawn from A on the front projection diagram to intersect the line OU on the side projection diagram at point A'. Then, A' is the position of A on the side projection diagram. On the side projection diagram, A'L = α is measured horizontally forward from point A', and A'L' = β is measured horizontally backward from point A', where the values of α and β can be directly obtained from the tangent plane as shown in Fig. 5. Figure 2cThe measurements are shown. Then, on the orthographic projection, take an arc A1S1 = b'. S1 on the side projection is the position of point S on the orthographic projection. Draw a horizontal line from point S1 on the orthographic projection and intersect it with the perpendicular line drawn downwards from point L on line A'L. Point S' is then the point on the side projection outline of point S. Similarly, draw a horizontal line from point H1 on the front view and intersect it with the perpendicular line drawn downwards from line A'L' at point H'. Point H' is then the point on the side projection outline of point H at a point along the edge.

[0057] Figure 2c-2a The diagram shows the stretching profile, front view, and side view of the cross section at radius r. Figure 3c A schematic diagram showing the propeller extension profile; Figure 3b A schematic diagram showing the front view of the propeller; Figure 3a The image shown is a schematic diagram of the propeller's side view. Figures 3a-3c ,use Figures 2a-2c The method shown involves connecting the corresponding points on the projected profile at each of the other radii with a smooth curve to obtain the projected profile. Following the above steps, it is common practice to draw the profile based on cross-sections at eight or nine radii of the blade, with corresponding radii r = 0.2R, 0.3R, 0.4R…0.9R (0.95R).

[0058] like Figures 3a-3c The drawing logic of the 2D overall diagram shows that the extension profile at each characteristic radius of the propeller serves as the basis for drawing the front and side views of the propeller, and the surface data of the extension profile is determined by Tables 1 and 2. Specifically, the surface data of the extension profile (such as blade width, maximum thickness, and distance from the guide edge to the thickest point at each radius) comes from Table 1 (blade profile dimension table) and Table 2 (blade cross-sectional dimension table). These tables store standardized data for specific propeller types (such as the AU type) at different radii. Therefore, during the 3D modeling process, the 3D drawing unit reads the surface data at each radius in Tables 1 and 2 and automatically draws a cross-sectional sketch at that radius on the corresponding radial plane. These sketches accurately reproduce the shape of the cross-section in the extension profile, including the curvature of the guide edge, the tilt angle along the edge, and the thickness variation trend.

[0059] Step S4: The three-dimensional drawing unit extracts information on multiple key feature points at multiple feature radii from the two-dimensional overall drawing and draws a three-dimensional model.

[0060] Specifically, the feature radius extracted in step S4 is consistent with the feature radius selected in step S2 when drawing the parameter drawing propeller two-dimensional total map. Specifically, 8-9 feature radii (r=0.2R, 0.3R, 0.4R…0.9R(0.95R)) are selected in S2 as the drawing reference, so the three-dimensional drawing unit in step S4 also selects 8-9 feature radii (r=0.2R, 0.3R, 0.4R…0.9R(0.95R)) as the drawing reference to maintain the correspondence of the data.

[0061] Specifically, the information of the key feature points includes the coordinates of the key feature points and the transmission relationship data of the view. Specifically, the coordinates of the key feature points include: the plane coordinates (x1, y1) of the leading edge point (J), the trailing edge point (H), and the maximum thickness point (S) at each radius in the stretch contour map, including the thickness distribution, chord length, and other morphological data of the cross section; the orthographic projection coordinates (x2, y2) of the above feature points in the orthographic projection map, reflecting the positions of the feature points in the radial direction (radius r) and the circumferential direction (angle θ); the side projection coordinates (x3, y3) of the above feature points in the side projection map, reflecting the offset amount of the feature points in the axial direction (z direction). Specifically, the projection relationship of the view includes: the pitch angle (θ) at each radius, the axial offset amount (α, β) of the leading edge / trailing edge, etc.

[0062] Step S5: The three-dimensional drawing unit draws a three-dimensional model according to the information of the plurality of key feature points at the plurality of radii.

[0063] Specifically, the three-dimensional drawing unit draws a three-dimensional model according to the information of the plurality of key feature points at the plurality of radii includes:

[0064] S51: converting two-dimensional coordinates into three-dimensional coordinates;

[0065] Specifically, based on the projection relationship, the extracted two-dimensional feature point coordinates are converted into three-dimensional space coordinates: the radial coordinate (r) and the circumferential angle (θ) of the orthographic projection map are used as the radial and angular parameters of the three-dimensional coordinates; the axial offset amount of the side projection map is used as the axial parameter (z) of the three-dimensional coordinates; the cross-sectional size (such as thickness) of the stretch contour map is combined to determine the coordinate of the feature point in the thickness direction, forming a complete three-dimensional point set, for example, the three-dimensional coordinates of the leading edge point J are (r, θ, z1).

[0066] S52: generating a spatial contour line;

[0067] Specifically, the same type of feature points (such as all leading edge points, trailing edge points) are fitted by a spline curve to generate a spatial profile curve in order of feature radius from small to large. The leading edge spatial curve: connects the three-dimensional coordinates of the leading edge points at each radius, reflecting the spiral direction of the blade leading edge from the root to the tip; the trailing edge spatial curve: connects the three-dimensional coordinates of the trailing edge points at each radius, together with the leading edge curve to define the radial width of the blade; the maximum thickness spatial curve: connects the three-dimensional coordinates of the maximum thickness points at each radius, providing a reference for the thickness distribution of the blade.

[0068] S54: three-dimensional section construction;

[0069] Specifically, according to the pitch angle θ, the normal vector of the section plane is adjusted to (sinθ, 0, cosθ) to ensure that the section is perpendicular to the spiral line direction (consistent with the direction of the NN` line in the stretch profile diagram). The shape of the section at this radius in the stretch profile diagram (based on the plane coordinates of J, H, S points) is projected onto the three-dimensional section plane, where: the connecting line of the leading edge point J and the trailing edge point H is the chord line of the section, with a length equal to the chord length L in the stretch profile diagram; the distance from the maximum thickness point S to the chord line is T / 2 (half thickness), and the profile lines on both sides (leading edge side and trailing edge side) are generated according to the thickness distribution curve of the stretch profile diagram.

[0070] S55: blade surface solidification;

[0071] Specifically, taking the leading edge spatial curve and the trailing edge spatial curve as boundaries and the three-dimensional section at each radius as a cross section, the lofting command is executed, and the three-dimensional platform automatically calculates the transition surface between adjacent sections.

[0072] S56: multi-blade assembly;

[0073] Specifically, taking the propeller axis as the center, the interval angle (360° / n) is calculated according to the number of blades input by the user, and the single-blade is executed with a rotation array operation, such as 4-blade propeller with a blade interval angle of 90°, copied 3 times; 5-blade propeller with a blade interval angle of 72°, copied 4 times.

[0074] Through the above steps, the three-dimensional drawing unit has completed the conversion from two-dimensional feature points to three-dimensional entities, and the entire process strictly follows the projection relationship and size constraints of the two-dimensional general drawing, ensuring that the three-dimensional model not only meets the design parameters, but also accurately reflects the spatial form of the propeller.

[0075] Optionally, it also includes S6: surface quality detection and structural strength detection on the three-dimensional model. Based on the three-dimensional model generated in the early stage, the geometric form of the propeller blade section is checked and adjusted to solve the problems of surface discontinuity and local insufficient strength caused by simply relying on the airfoil table data, providing a reliable model for subsequent manufacturing and use.

[0076] Specifically, the curved surface quality detection and structural strength detection content includes: detecting the smoothness of the tangent curve: verifying the continuity of the tangent curve (leading edge, trailing edge and thickness distribution curve) at each feature radius, ensuring that there is no curvature mutation (such as sharp corners, folds) except the trailing edge endpoint. Specifically, the tangent sketch at each radius is called through the three-dimensional software platform, and the curve curvature change is intuitively viewed; if there is a curvature mutation, the curve control point (such as the center position of the leading edge arc, the slope of the trailing edge curve) is manually adjusted, or the smooth curve function of the software is automatically optimized until the curve is continuous and smooth.

[0077] The size of the arc at the leading edge of the propeller blade section: The radius of the arc at the leading edge endpoint is focused on, specifically, the size of the leading edge arc at 0.8R is focused on, and the radius r needs to satisfy r=(0.004~0.005)b, b is the chord length at the radius. The reason is that because the section of the propeller blade operates in a non-uniform wake field, the arc at the endpoint has a great relationship with the performance of the propeller, especially the cavitation performance. Therefore, it is more beneficial to appropriately increase the arc at the leading edge endpoint near the blade tip. The size of the arc r at the leading edge endpoint is related to the area of the blade, the section profile shape and the thickness, so it can be appropriately increased or decreased in actual design.

[0078] The thickness of the trailing edge near the blade tip: In engineering practice, the trailing edge near the blade tip is prone to damage due to large water flow impact force and thin structure, which affects the performance and service life of the propeller, so it needs to be appropriately thickened. Specifically, the thickness of the trailing edge at 0.9R~0.95R (near the blade tip) is focused on, and whether it meets the strength requirement is verified. The thickness data of the section near the blade tip (the original data comes from Table 2) is called, if the thickness is insufficient, the local thickness of the trailing edge is manually increased; if the thickening leads to discontinuity of the local section shape (such as thickness mutation), the size of the region is slightly modified (such as fine-tuning the slope of the trailing edge curve) according to the airfoil table, and the discontinuity is eliminated through the smooth function of the software to ensure the overall curved surface smooth.

[0079] The three-dimensional model construction method of the propeller provided in the application uses the core parameters (blade type, number of blades, pitch, etc.) input by the user and the airfoil table data, and the model construction module can automatically complete the two-dimensional general drawing and three-dimensional model generation, without manually drawing sections and splicing curved surfaces, greatly improving the three-dimensional modeling method of the propeller.

[0080] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method of constructing a three-dimensional model of a propeller, characterized by, Comprise: Build a three-dimensional modeling platform, the three-dimensional modeling platform includes user interaction interface and model construction module, the model construction module includes two-dimensional drawing unit and three-dimensional drawing unit; The user interaction interface inputs drawing parameters to the modeling platform, the drawing parameters include the propeller type, the number of leaves, the pitch of the propeller; The two-dimensional drawing unit draws a two-dimensional total drawing of the propeller according to the drawing parameters, the two-dimensional total drawing includes an orthographic projection, a side projection and a stretch contour drawing; The three-dimensional drawing unit extracts information of a plurality of key feature points at a plurality of characteristic radii from the two-dimensional total drawing; the three-dimensional drawing unit draws a three-dimensional model according to the information of the plurality of key feature points at the plurality of characteristic radii.

2. The propeller three-dimensional model construction method according to claim 1, characterized by, The three-dimensional modeling platform further comprises a data processing module for storing user input parameters and a database of multiple types of propeller blades.

3. The propeller three-dimensional model construction method according to claim 2, characterized by, The database of multiple types of propeller blades includes AU propeller, MAU propeller blade profile size table and blade section size table.

4. The propeller three-dimensional model construction method according to claim 1, characterized by, The two-dimensional drawing unit according to the drawing parameters to draw a two-dimensional total drawing of the propeller comprises: Determine the propeller parameters, the propeller parameters include the number of propeller blades, the disc ratio and the diameter of the propeller; Select a plurality of characteristic radii; Obtain the key parameters at the plurality of characteristic radii according to the blade profile size table and the blade section size table; According to the above parameters, the stretch contour drawing, the orthographic projection and the side projection are drawn in turn.

5. The propeller three-dimensional model construction method according to claim 4, wherein, The characteristic radii extracted by the three-dimensional drawing unit from the two-dimensional total drawing are consistent with the characteristic radii selected by the two-dimensional drawing unit when drawing the two-dimensional total drawing of the propeller.

6. The propeller three-dimensional model construction method according to claim 1, wherein The three-dimensional modeling platform is an OLE automation server, and the control of the three-dimensional modeling platform is realized through programming language.

7. The propeller three-dimensional model construction method according to claim 1, characterized by, Also include: Carry out surface quality detection and structural strength detection on the three-dimensional model.

8. The propeller three-dimensional model construction method according to claim 7, wherein, The content of the surface quality detection and structural strength detection on the three-dimensional model comprises: Detect the smoothness of the section curve; The size of the circular arc at the section guide edge of the propeller blade; The thickness of the section along the edge near the blade tip.

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